Giant basilar tip aneurysms are a challenge to treat because of the complex anatomy and critical vessels that arise in this region. For large aneurysms, with multiple recurrences after coiling, when microsurgical clipping is not possible, a bypass to the posterior cerebral artery (PCA) can be helpful in providing definitive treatment. Two patients with giant basilar tip aneurysms were treated with bypass to the PCA. One patient had a microsurgical clipping and the other had a proximal occlusion of the basilar artery along with the bypass. Long-term angiographic and clinical follow-up was obtained. One patient had marked improvement in symptoms and a stable aneurysm remnant and the other patient had complete occlusion. Surgical treatment with a bypass to the PCA, with clipping of the aneurysm or proximal ligation of the basilar artery can be an effective treatment option for giant basilar tip aneurysms.